Data from: Plant competitive interactions and invasiveness: searching for the effects of phylogenetic relatedness and origin on competition intensity

The invasion success of introduced plants is frequently explained as a result of competitive interactions with native flora. Although previous theory and experiments have shown that plants are largely equivalent in their competitive effects on each other, competitive non-equivalence is hypothesized to occur in interactions between native and invasive species. Small overlap in resource use with unrelated natives, improved competitiveness and production of novel allelochemicals are all believed to contribute to the invasiveness of introduced species. I tested all three assumptions in a common-garden experiment by examining the effect of plant origin and relatedness on competition intensity. Competitive interactions were explored within 12 triplets, each consisting of an invasive species, a native congeneric (or confamilial) species and a native heterogeneric species that are likely to interact in the field. Plants were grown in pots alone or in pairs and in the absence or presence of activated carbon to control for allelopathy. I found that competition intensity was not influenced by the relatedness or origin of competing neighbors. Although some exotic species may benefit in competition from larger size and species-specific effects, none of the three mechanisms investigated is likely to be a principal driver of their invasiveness.RAWDATAExcel file with entries of final plant biomassRAWDATAgraphsGraphs showing mean plant biomass of invasive, native congeneric and native heterogeneric plants grown alone or in competititio